Psychology 485
September 28, 2010
 Introduction
& History
 Three major questions:
• What is learned?
• Why learn through classical conditioning?
• How does learning happen?
 Often
contrasted to more cognitive
approaches
• Watson & Little Albert
A
premise: Study of simple learning
processes will “scale up” to complex
cognition
 Pavlovian
(Classical)
conditioning
 Physiologist
 Digestion
• Dogs
 Conditional
redirection of
reflexes
 Conditional reflexes
TIME
Conditional
Stimulus
Unconditional
Stimulus
on
off
on
off
(after enough
pairings)
Conditional
Response
Unconditional
Response
 “The
originally neutral stimulus, through
repeated pairings with the unconditioned
one, acquires the response originally
given to the unconditioned stimulus”
• Intro Psych textbook from 1987
 What
is wrong with this definition?
 Taste
aversion
 Idea of contiguity
• Temporal similarity between presentation of CS
and US
• i.e. CS and US are presented at the same time
 Contiguity
necessary
is neither sufficient nor
Group
Initial
Training
Second
Training
Test
Outcome
Control
Group
Nothing
Tone + Light
 Food
Light  ?
Moderate
response to
Light
Blocking
Group
Tone  Food
Tone + Light
 Food
Light  ?
Little
response to
Light
 During
second training, tone & food are
contiguous
 Contiguity not sufficient
CS1
CS2
 Which
CS would condition more easily?
• Contiguity is the same
 CS2: US
is contingent (dependent) on CS
 Contingency, not contiguity
CS1
 No
contiguity between CS and US
 CS signals absence of US
• Conditioned inhibitor
 Contiguity
is not necessary for
conditioning
 “The
originally neutral stimulus, through
repeated pairings with the unconditioned
one, acquires the response originally
given to the unconditioned stimulus”
• Intro Psych textbook from 1987
 CERs
(Conditioned Emotional Response)
• Pair tone with shock
• When rat is shocked, it jumps and increases
activity
• What tone is presented, rat freezes
 Drug
tolerance
• CSs for drug use cause body to prepare for drug
• Body prepares in opposite direction of drug
 Context
 Hierarchical
structure
• Second-order conditioning
• Occasion-setting
 Expectancies
 What
type of association is formed?
• Stimulus-Stimulus
• Stimulus-Response
US
CS
Response
 So, how
do you get rid of a response that
is hard wired to a stimulus?
 How can you get rid of a reflex?
• Habituation
Group
Phase 1
Habituation L  N
(startle)
Control
LN
(startle)
 Less
Phase 2
Test
Noise
Light
(habituate)
Nothing
Light
suppression in Habituation group
• (In other words, more responding)
 Therefore, the
connection MUST be S – S
Noise
Light
Startle
 Expectancies
• CS helps you predict occurrence of US
• Makes animal more able to react to US
 Biological
relevance
• Not all CSs are created equal
• e.g. ‘bright-noisy’ water vs novel-tasting water
 Hard to condition visual/auditory stimuli to nausea
 Blue
Gourami
• Territory is defended
more aggressively when
competitor is signaled
• Winners become winners
• Losers stay losers
 Japanese
Quail
• Signalling opportunity
for reproduction
• Increases effectiveness of
copulation (quicker and
more ejaculate)
• Increases likelihood of
fertilization
 Ant
Lions
• Signal food
presentation for larvae
• Build better pits
• Extract food more
effectively
• Moult more quickly
(quicker to reproduce)
 Baldwin
effect
• If there is a reliable predictor of some important
event across generations:
 Learning faster is better
 Learning becomes instinct?
• e.g. New predator in environment
 Some behaviour makes it difficult for predator to kill prey
 Learning behaviour provides survival advantage
 Selection: ability to learn improves
 Eventually behaviour becomes instinct
 Computational
model of conditioning
• Widely cited and used
• Most important paper in animal learning?
 Learning
as a violation of expectations
Error Calculation

On every trial:
1. Look around and examine all your stimuli
2. Use them to predict what will happen (V∑)
3. Get a reward/US. How good/big was it? (λ)
4. How wrong was your prediction? (λ - V∑)
5. Take a portion of that error (α and β)
6. Change your prediction for next time (ΔV)
 And Voila! You
have a learning algorithm.
ΔV = αβ(λ - V∑)






λ = the maximum conditioning possible
α = saliency of the CS (between 0 and 1)
β = saliency of the US (between 0 and 1)
VX= associative (predictive) strength of a given
stimulus
ΔVX= change in the associative strength of a given
stimulus
V∑ = total associative strength of all stimuli
 Equation
describes a change in
expectancies
 Change in expectancy is based on:
• Features of the CS and US
• Total possible learning, minus what you’ve
already learned
 Based
on expectation of US
 Does
not account for many Classical
Conditioning findings:
• Spontaneous recovery
• Savings
• CS pre-exposure (latent inhibition)
• Higher-order conditioning
 Trial-by-trial
based account
• Does not account for timing
 CS
processing theories suggest
properties of CS affect learning
• Attentional theories: it’s adaptive to pay
attention to CSs that may signal important events
• Also adaptive to not pay attention to CSs that are
not likely to signal important events
 Pearce-Hall
model
• Attention to CS changes across trials
• α can change from trial to trial